Liquid crystalline structures are well ordered structures that can hold active ingredients, yet restrict the diffusion of the active ingredients to facilitate a controlled release of the active ingredients. However, some of the components used to create these cubic crystalline phases can be difficult to incorporate into such phases. For instance, monoglycerides have some undesirable physical characteristics such as a high melting point that makes the monoglycerides pastes or waxy solids at room temperature. Further, the equilibration time required to form the monoglycerides into such structures may be several hours or days since the diffusion of water through the solid monoglycerides is delayed.
Another problem is that the processes used to form the cubic, liquid crystalline phases are cumbersome since such processes require long holding times, high manufacturing temperatures, and high shear processes that are not economically or commercially viable.
Lecithin organogels are clear, thermodynamically stable, viscoelastic, and biocompatible jelly-like phases typically having hydrated, purified phospholipids, an organic liquid, and a gelating agent. The purified phospholipids that are usually used contain at least 80-95% phosphatidylcholine content to prepare the organogel. A limitation of such organogel formation requires the use of such highly pure lecithin that is expensive and not easily obtained.
Another limitation in the formation of such lecithin organogels is the polymer that is typically used. For instance, the synthetic polymer, pluronic, has been used in lecithin organogels at an amount of between about 30-40%. However, pluronics are non-ionic triblock copolymers which may be characterized as a skin irritant, are not bio-based, not allowed in food systems, and are not inexpensive compounds.
Thus, a need exists for organogels that are easier to manufacture and that use bio-based and/or food-grade components.